Modifiable condenser



May 23, 1933. c DRAVING I 1,910,987

MODIFIABLE CONDENSER Filed Jan. 23, 1932 3 Sheets-Sheet l IA V17 T012 CZWJGS (la 221mm Patented May 23,- 1933 CHABLES H. DRAVDIG, OF PHILADELPHIA, PENNSYLVANIA koDIFIABLE contonusnn Application filed January 23, 1932. Serial No. 588,297.

My invention relates to new and useful improvements in a modifiable condenser and has for one of its objects to provide a device of' this character in which alternate fixed plates have taps or contact lugs for engagement with a contact shoe to selectively increase or decrease the condenser couples for changing the condenser effect or caacity. v r

Another object of the invention is to provide a multiple stationary plate condenser wherein the eifect of alternate plates may be selectively added and subtracted while only one of said alternate plates is provided with a lead for connection to a desired radio or electrical circuit and wherein all of the intermediate plates are provided with a common lead for connection to the radio or an electrical circuit.

Another object of the invention is to provide a case or housing of unique construction in which the condenser plates and component parts as well as the operating elements are completely enclosed.

Another object of the invention is to con- 'struct the several condenser platesin the form of discs each having lugs, the lugs on some of the plates being utilized as contacts and those of others of the plates beingused .for connection to a load.

Another object of the invention is to construct a contact shoe that may be easily mounted and held in place and provide posi v tive engagement with the contactlugs.

Another object of theinvention is to pro- ,vide means for holding the plates in place including'a disc of insulatingmaterial provided with projections which hold the con.- 4o tact lugs, or portions thereof, in the longitudinal slots in the side wall of the casing.

Another object of the invention is to so construct the bushing that it-will form slots or grooves in the walls of the opening in the housing which receives the bushing 'wherebysaid bushing will be held in place with suflicient friction to prevent its accidental displacement.

Another object of the invention is to provide the bushing with stop shoulders for coaction with the stop finger mounted on the rotatable shaft.

A further object of the invention. is to provide a modifiable condenser consisting of two main parts either of which may be rotated relative to the other for changing the capacity of the condenser, one of said. parts including a contact shoe and component elements and the other part including.

a series of alternate plates and component elements, said alternate plates being provided with contact lugs for cooperation with 'the contact shoe.

In order that those skilled in the art to Y which this invention appertains may understand how to make and use the same, I will describe its construction in detail, referring by numerals to the accompanying drawings forming a part of this application, in' 89 which '1 Fig. 1 is a plan or end view of a condenser constructed in accordance with my invention. with the cover removed.

Fig.2 is a side elevation thereof with the cover in place and a portion of the shaft. broken off since the latter may be of any desired length.

' Fig. 3 is a plan or end view of the contact. shoe and stop assembly.

Fig.4'is an edge view thereof with a portion of the shaftbroken away.

Fig. 5 is a face view of the disc of insulating material provided with projections by which portions of the condenser plate con tact lugs are held in place.

Fig. 6 is an edge view thereof.

Fig. 7 is an edge view of one of the alternate condenser plates illustrating the arrangement of the contact lugs.

to provide a shoulder 37, and saidreduced- Fig. 8 is an outer face view thereof.

Fig. 9 is an enlarged fragmentary sectional view on about the line 99 of Fig. 8.

Fig. 10 is an enlarged section on the line 1010 of Fig. 1, with the contact shoe over the majority of the contact lugs and with the shaft left in elevation.

Fig. 11 is an enlarged fragmentary sectional view of the casing on the line 1111 of Fig. 1, and with the other parts left in elevation except for portions of the condenser plates and the single or independent lug and the cover removed. A

Fig. 12 is a view similar to Fig. 11, but with a less number of parts shown illustrating a modification.

Fig. 13 in an enlarged broken fragmentary sectional view of the condenser to illustrate the method of bringing the lugs of the intermediate condenser plates together, said section being-on the line 1313 of Fig. 1.

Fig. 14 is a fragmentary end or plan view of the casing per se, on a slightly reduced scale and illustrating the longitudinal slots in the side wall.

Fig. 15 is a face view of the contact shoe.

Fig. 16 is an edge view thereof.

Fig. 17 is a face view of one of the insulating washers. v

Fig. 18 is an edge view thereof.

Fig. 19 is a face view of the spring washer.

Fig. 20 is an edge view thereof.

Fig 21 is an inner face view of the stop finger and its supporting body.

Fig. 22 is an edge view thereof.

Fig. 23 is an inner end view of the sleeve for the operating shaft having the flange thereon in which the stop shoulders are formed.

Fig. 24 is a side elevation thereof.

1 Fig. 25 is a face View of the independent ug. Fig. 26 is an edge view of the same.

Fig. 27 is a diagram of the condenser il lustrating how it can be connected into a radio or an electrical circuit.

In carrying out my invention as herein embodied, 30 represents the casing or housing which is preferably produced from insulating material, although it will be understood that if the parts are properly insulated said casing could be of any desired material. The casing comprises an end wall 31 preferably having a hub 32 through which a bore 33 is formed, and a side wall 34 having at least two apertures 35 and 36 formed therethrough in the region of the end wall 31. The end of the casing or housing opposite the wall 31 is open and the edge is slightly reduced from the inside in order edge is undercut as at 38 to receive the edge of the cap, cover or closure 39, which is preferably sprung into place.

Around the inside of a portion of the side wall are formed suitably spaced longitudinal grooves 40 and said grooves should be of a number equal to the alternate plates which are provided with contact lugs and in which portions of said contact lugs are located as will be obvious from the later description, and said grooves preferably are of a depth equal in thickness to the portion of the side wall between its inner face and the inner face of the reduced edge of said side wall.

In the inner face of the end wall 31, adjacent the aperture 35, is formed av recess 41 of the same outline as the inner end of the independent lug 42, Figs. 25 and 26, which lug is mounted in the recess with its outer end protruding through the aperture 35 and said recess is of a depthslightly less than the thickness of said lug'42 so that the innermost one of the series of alternate condenser plates-43 will directly engage and contact with the recessed end of said independent lug 42.

Interposed between the adjacent alternate plates 43 are intermediate condenser plates 44. The term intermediate is used only to better identify and differentiate between the two sets or series of condenser plates. The contiguous condenser plates, that is the plates of both series, are suitably insulated fromeach other in any desirable manner but preferably by dielectric mediums 45, such as wax paper, mica or the like.

All of the condenser plates are full circles as will be obvious by reference to Fig. 8, and for convenience of description they will be referred to as discs, each having a central opening 46 for the. passage of the sleeve and its enclosed shaft. alternate condenser plates 43 is provided with an offset 47 on its perimeter and from the offset projects a contact lug 48 which where said lug and offset join, said lug is Each of the I slightly narrower than the offset to provide shoulders 49. The offset and lug are in fact one element so that the offset may be considered as a part of the lug which is formed integral with the plate. From the offset the lug extends outwardl perpendicular to the plate for a suitabletistance and the end is then bent over the plate in spaced relation thereto and said inwardly bent portion of brought into absolute engaging relation so that a common lead conductor can be fastened to all of them, and for this purpose .a

' parts of the contact lugs in order to hold .said perpendicular parts inthe grooves and displacement or rotation.

sufficient length to project beyond the outer hole 52a, Fig. 1, may be provided through each terminal lug. For the same purpose, a hole 53a may be formed inthe outer .end of the independent .lug 42.

\Vith the condenser plates in position as shown in Figs. 10, 11 and 13, the contact lugs 48of the. alternate plates will be arranged in an arcuate position as shown in Fig. 1, with the parts. of said contact lugs, which are perpendicular to the -plates, located in the grooves 40 of the case o'rhousing. A partially serrated or scalloped disc' 52 of insulating material is imposed on the outermost condenser plate with the circumferential serrations, scallops or projections 53 in engagement with the perpendicular thereby prevent displacement of the contact lugs, and said projections 53 may actually extend into the grooves or as much of the grooves as is unfilled by the perpendicular portions of the contact lugs. Said disc 52 is provided with a central opening 54. j

Directly on top of the serrated or scalloped insulating disc 52 is mounted a metallic holding washer 55 which is -'finally engaged by the flange 56 of the sleeve 57, the latter being passed through the holding washer, the hole 54 in the partially scalloped disc 52 and the condenser plate assembly and into the hole 33 of the casing which hole is slightly smaller than the two spaced bands of knurling 58, the latter being fashioned so as to shave or cut their own grooves in the casing and when the sleeve 1s 1n place,,

it will be securely held against accidental The sleeve is of surface of the end wall of the casing and said outer projecting end is provided with threads 59 so that a nut 60 may be run thereon and may be utilized for mounting the condenser on a radio panel or other support, but saidnut is not particularly used for holding the sleeve in place, although it will accomplish this purpose and would hold said.

sleeve against displacement under extraordinary conditions. By spacing the two bands of knurling, any of the material of the casing which happens to be displaced can be taken care of or-accommoda d.

'A portion of the flange 56 of the sleeve is cut away in order to provide a pair of,

stop shoulders 61 to be engaged at different times by a'stop finger to be later described. A shaft 62 is mounted in, the sleeve with the ends of said sleeve, and the inner end of said shaft is suitably reduced in size'to produce a shoulder-63; a neck 64 on \which is formed a head 65. On the neck 64 of the shaft between the shoulder and head is mounted a metal washer 66 engaging the shoulder and providing a suitable supporting surface for an insulating washer 67 superimposed thereon which washer has a notch 68 in its periphery and upset teats 69, preferably two in number and said teats register with the holes 70- in the contact shoe 71, the latter having an opening 72 for registration with the neck of the shaft, but larger than said neck so as not to be in contact therewith.

, Said. contact shoe includes a hub 73 in which the holes 70 and the opening 72 are formed, and an arcuate approximately semicircular contact bridge 74 of sufiicient length to bridge allof the contactlugs 48 when in the operative position and the forwardend, considered as when being moved into the operative position, is turned outward as indicated at 75to provide a tongue which will readily pass over the contact lugs. 1 The hub has a notch 76 formed in the edge thereof which registers with the notch 68 in the washer 67 just below the contact shoe.

Another insulating washer 67 identical in construction with the first mentioned one is imposed on the contact shoe 71 so as to provide insulating material between said contact shoe and the body 77 of the stop 78, said body functioning as a washer between the outer insulating washer 67 and the'head of the operating shaft. Said outer insulating washer need not be provided with the teats 69, but since they do not interfere with the operation of the. device in anyway they- .can be left on and eliminate the making of of the metal of said head will be forced 7 into the notches, thereby securelyvfastening the stop on the shaft to prevent rotation of one relative to the other. 'From! the body projects an arm 81 of suflicient length to reach the notches 68 and 76 at which point a finger 82 projects inwardly at right angles to thearm and extends through or registers with or is seated inthe notches 68 of both insulating washers 67, and the notch 76 in the hub 73 of the contact shoe 71 and lies againstthat portion '1 of "the flange 56 of smaller diameter at the inner end of the ders '61 to limit the movements of the .operating shaft and the contact shoe as well as their component parts of the assembly illustrated in Figs. Band 4.

sleeve 57 for. coaction with. the 'stop shoul-i When' the shaft is mounted in the sleeve I 57, a spring washer Figs. 10, 19 and 20 in particular, is interposed between the metal washer 66 and the flange 56 of said sleeve so as to normally force or tend to force the contact shoe and its assembly away from the sleeve in order to provide the necessary friction for holding the rotating parts in any adjusted position. the movement of the shaft and component parts due to the force of the spring washer being limited by a split washer or collar S-l which is forced into the circumferential groove 85 in the shaft in the region of the outer end of the sleeve. and said split washer or collar engaging the outer end of the sleeve, accidental displacement will be prevented of the operating shaft and its assembly.

In order to hold the perpendicular parts of the contact lugs 48 in place, a washer S6 of insulating material may be placed in the casing so as to surround the flange of the sleeve and engage the perpendicular portions of the contact lugs at the points where the oblique portions of said lugs begin and it is said oblique portions that have the resiliency to normally lie beyond the contact surface. of the contact shoe. but will be depressed as said shoe moved thereover. said shoe being guided over the contact lugs by the tongue 75 and thereafter the said contact lugs will be in resilient engagement with the contact shoe.

In the modification illustrated in Fig.12. the single terminal lug 42 is formed as an integral part of the body 41 which body is of the same size as the condenser plates. and said terminal lug -12 projects through the aperture 35 in the same way as the independent single terminal lug 4:2.

In actual use. the single terminal lug is connected by a wire or other suitable conductor 87. Fig. 27'. with any desirable part of an electrical or radio circuit. while all of the intermediate condenser plates have a common connection by a wire or other suitable conductor 88 with another or some other part of the same or another electrical or radio circuit according to the use to which the condenser is put.

- By reference to Fig. 27. it will be noted that when the contact shoe 71 is moved across the contact lugs 48, the several couples of the condenser will be made or broken, thereby gradually changing the capacity of the condenser without actually moving any of the plates.

Of course I do not wish to be limited to the exact details of construction as herein shown, as these may be varied within the limits of the appended claims without departing from the spirit of my invention.

Having thus-{fully described my invention, what I claim as new and useful is 1. In a device of the kind described, a. casing having a side and oneend wall providing a housing for condenser elements,

said side wall having cireumferentially spaced longitudinal grooves about a portion of its inner face and further provided with apertures extendingthrough the side wall and into a portion of the end wall.

2. The structure set forth in claim 1, in combination with fixed condenser plates including alternate and intermediate ones, said intermediate plates having terminal lugs, all of which project through one of the apertures for connection with a common conductor, a terminal lug associated with one of the alternate plates and projecting through the other aperture for connection to another conductor, contact lugs carried by the alternate plates and having portions thereof located in the longitudinal grooves and means to successively bridge said contact lugs for changing the condenser capacity.

3. In a device of the character described, a series of full circular fixed condenser plates suitably insulated from each other and constituting alternate and intermediate plates, an integral offset 011 the perimeter of each plate. a lug of less width than the offsetformed integral with and projecting from said offset, shoulders formed on thev outer ends of the offsets at both-sides of the lugs, the lugs on the intermediate plates constituting terminals while the lugs on the alternate plates constitute contact elements.

4. The structure set forth in claim 3, in combination with contact buttons formed on the free ends of the contact elements.

In a device of the kind described, a contact shoe assembly comprising a shaft having a reduced end constituting a neck, a shoulder formed between the circumferences of the shaft and neck, a head formed on the outer end of the neck, a metal washer on the neck in engagement with the shoulder. a asher of insulating material having teats projecting therefrom, a contact shoe having holes for registration with said teats, another washer of insulating material imposed on the contact shoe and means interposed between the last mentioned insulating washer and the head functioning as a washer and including an arm and finger extending over the edges of the insulating washers to function as a stop.

6. The structure set forth in claim 5, wherein the contact shoe consists of a hub in which the holes for the teats are formed, an arcuate contact bridge, and a tongue bent outward from one end of said bridge[ 7. In a device of the character described, a casing including an end wall having an opening therethrough. said casing adapted to contain the elements of a condenser and a sleeve to hold some of the condenser elements in place and function as a bearing for an operating shaft and knurling on the exterior of said sleeve which will cut into the ing, whereby said sleeve wilt-be fixed against accidental displacement.

8. A modifiable condenser including a casing having a side and oneend wall, said side wall being provided with a series of cireumferentially spaced longitudinal grooves and also provided with apertures adjacent the end wall extending through said side wall and into said end wall, said I end wall having arecess in its inner face adjacent one of the apertures and further provided with a central opening. an interior circumferential shoulder formed on the side wall adjacent the open ,end of the casing, an undercut rim beyond the shoulder, a cap having its edge engaging the shoulder and underlying the undercut rim of the casing, an independent terminal lug seated in the recess with a portion projecting through the contiguous aperture, a series of condenser plates of disc form having central openings therethrough and constituting alternate and intermediate plates, said plates being fitted in the casing with the innermost alternate one in contact with the independent terminal lug, lugs formed with the intermediate plates and all of them projecting through the other aperture for connection to a common lead, contact lugs formed with the alternate plates with portions fitted in the longitudinal grooves of the casing and other portions projecting inwardly: toward the common axis of said plates, a disc of insulating material having a central opening, projections formed on the perimeter of said disc to engage and hold portions of the contact lugs in the longitudinal grooves, said disc being imposed on the outermost condenser plate, a metal Washer imposed on said insulating disc, a sleeve projecting through the opening in said washer, the insulating disc, the condenser plat'es and the end wall of thecasin g, knurling on the exterior of the sleeve intermediate its ends to cut into the casing material as said sleeve is mounted in place, the

"outer end of said sleeve being exteriorally threaded, a flange formed on the inner end of said sleeve to engage the metal washer ,and a portion of said flange being cut down to provide stop shoulders, an insulating wash= 1 er surrounding said flange with the perimeter of said washer in proximity to the parts of the contact lugs which are fitted in the longitudinal grooves, an operating shaft mounted in the sleeves, said shaft having a circumferential groove adjacent the outer end of the sleeve, a split ring in said groove to normally limit the inward movement of the shaft, a shoulder at the inner end of the shaft, a-ne'ck of smaller diameter than the shaft" projecting therefrom, a metal Washer mounted on the neck and engaging the shoulder, a pair of spaced insulating Washers mounted on said neck w1th one of them in engagement with the metal washer which is also on the neck, both of said washers having notches'in the circumference thereof and at least one of said washers having teats formed therewith and projecting from one face thereof, a contact shoe mounted between the insulating washers which are on the neck of the shaft, said contact shoeincluding a hub having a notch'in its edge coinciding with the notches in the contiguous insulating washers, and further provided with holes for registration withthe teats, a contact bridge carried by the hub for selective engagement with the contact lugs, an upturned tongue formed at one end of said bridge, a contact member including a body, an arm projecting therefrom and an int-urned finger, said body having an irregular hole for registration with the neck of the shaft and said finger extending through the coinciding notches and to the cut down portion of the sleeve flange for coaction with the stop shoulders to limit the movements of the contact shoe, a head tions thereof entering parts of the irregular opening in the body of the stop member I and aspring washer interposed between the flange of the sleeve and the adjacent metal washer on the neck of the shaft.

In testimony whereof, I have hereunto aflixed my signature.

' CHARLES H. DRAVING. 

